Linda Edna Cardellini (born June 25, 1975) is an American actress. She is known for her roles as Lindsay Weir on Freaks and Geeks, Samantha Taggart on ER, Velma Dinkley in the live-action Scooby-Doo feature films, Sylvia Rosen, neighbor of Don Draper's, on the AMC drama series Mad Men, Meg Rayburn on the Netflix original series Bloodline and Laura Barton in Avengers: Age of Ultron.